Rotary pump



Jan. 30, 1945.

A.'W. SAY 2,368,572

ROTARY PUMP Filed May 20, 1944 2 She ets-Shee t 1 Jan. 30,1945. w. SA 2,368,572

ROTARYPUMP Filed May 20, 1944 v 2 Sheets-Sheet 2 .z y uw 14% stitutes the PatentcdJan. 30, 1945 ROTARY PUMP Alan William Say, Upmlnster, England, assignor to The Plessey Company Limited, Ilford, England, a British company Application May 20, 1944, Serial No. 536,483 In Great Britain June 30, 1943 3 Claims.

videa simple and efficient dual pump system which can be arranged in a compact unit.

Hitherto single stage pumps of the kind referred to have been provided, wherein the pumping space or chamber is on the outside of the rotor.

In the accompanying drawings Figure 1 is a half section of the pump.

Figure 2 is a section at right angles to Figure 1. a

Figure 3 shows diagrammatically the two pumps connected in series, and

Figure 4 shows diagrammatically the two pumps connected in parallel.

According to this invention, two pumping spaces or chambers are provided, one within and one outside the rotor.

According to a feature of the invention the pumping spaces may be used individually to provide two separate pumping units, or in combination.

When used in combination, the two pumps may be connected in series so as to function as a two stage pump. In this case the outer pump pin, in association with end closure abutments.

Referring to the drawings, a rotor I mounted in journal bearings 2 is provided at one end with an extension shaft 3 for driving purposes. The other end of the rotor is formed with an enlarged diameter 4 which is slotted radially, and each slot 5 receives a sliding vane 6.

'The centre portion of said rotor is bored coaxially and in conjunction with the vanes 6, and a cylindrical centre pin I mounted in said bore and the slidlngly received abutment 8 conchamber of the inner pumping space 9.

The enlarged end 1- of the rotor I rotates within an eccentric sleeve III in the walls of which an inlet port "II and a delivery port I2 are provided, and is located axially between the end face of the journal bearing 2 and the face oi the end'cover l3 in which inlet port It and as The sliding abutment a isat or course an delivery port l5 serving the inner pump are machined.

The space between the enlarged end of the rotor 4 and the bore of the eccentric sleeve it constitutes tho outer pumpin space IS.

The outer pump as herein set forth has the enlarged end of the rotor 4 rotate within 'the sleeve HI having an eccentric'bore, the degree of eccentricity being such that a close running clearance is maintained at the point l1 between the wall of the sleeve on one side and the periphery of the rotor, so as to provide a fluid seal between the inlet port II and delivery port I2- which'are situated in diametrically opposite walls of the sleeve on an axis at to the line horizontally through the sealing point. These ports are carried round the periphery of the sleeve and are separated on the side diametrically opposite to the above mentioned sealing point 51, by a distance slightly in excess of the pitch of one pair of blades, so that a seal is always provided between the inlet and delivery ports on this side also. When the rotor turns the pumping space I6 is swept by the blades and fluid is displaced from the inlet to the delivery side of the pump.

For the inner pump the length-of the vanes 6, the diameter of the rotor bore 9 and the diameter of the centre pin 1 are proportioned so that the periphery of the centre pin abuts against the boundary of the rotor bore to form a fluid seal at the point l8. The ports and I5 machined-in the end coverli are separated on the side opposite to the sealing point i8 by a distance slightly in excess of the pitch of one pair of vanes so that a fluid seal between the inlet and delivery port is always provided on this side also. As in the case of the outer pump, rotation of the rotor assembly causes fluid to be displaced from the inlet to the delivery side of the pump, as the blades sweep round the centre pin. l

The chamber IS 'on the outer side of the sliding abutment 8 may be connected by the ducts 20 to the delivery port 15 of the inner pump, I thus the fluid pressure so communicated is caused to supplement the pressure exertedv by the spring 2| against abutment 8, so as to maintain contact between the face of the abutment and the centre pin I. By this means a close clearance'is maintained between the side faces of the inner pump, which is necessary to obtain a fluid seal, irrespective of variations in the intei'nal pressure in the pump.

essential feature since the spring 2| could be replaced by a solid spacer using shims to obtain the requisite axial location, or the abutment formed by a machined surface at the end of the rotor bore. 4

Such an alternative arrangement is preferable if the irmer pump is required to operate at high delivery pressures since the fluid pressure would not be communicated to the chamber l9 and the axial load exerted thereby on the rotor would therefore be eliminated.

Referring to the diagrammatic drawings in Figure 3 the outer pump 22is connected to the inlet 23 and the outlet therefrom is connected to the inlet of the inner pump 24 by duct 25. As the outer pump 22 is of larger capacity than the inner pump 24 a by-pass 26 with relief valve 21 is provided whereby excess capacity is returned to the inlet 23.

Referring to Figure 4 the two pumps 22, 24 are connected in parallel by means of a common inlet conduit 28 and common outlet duct 29.

L I claim:

1. A rotary pump comprising a stator provided with an eccentric chamber having an inlet and discharge port at diametrically opposite positions at the periphery of the chamber and an inlet and discharge port situated at opposite positions in. one face of the eccentric chamber, a rotor provided with a central bore and radial slots in communication therewith, a vane slidably mounted in each slot, a centre pin and an abutment in the central bore in said rotor, said centre pin located radially by the vanes, said rotor mounted in the eccentric chamber of the stator, the outer pump chamber formed between said stator and outer periphery of the rotor communicates with the peripheral inlet and discharge ports, the inner pump formed between the inner periphery of the rotor and centre pin communicates with the inlet and discharge portsin the face of the cylindrical chamberof said stator, and fluid pressure from at least one of the discharge ports acting upon the end of the sliding abutment within the central bore 'of the stator.

2. A rotary pump comprising a stator provided with an eccentric chamber having an inlet and discharge ports atdiametrically opposite positions at the periphery of the chamber and an inlet and discharge port situated at opposite positions in one face of the eccentric chamber, a rotor provided with a central bore and radial slots in communication therewith, a vane slidably mounted in each slot, a centre pin and an abutment sliding in the central bore in said rotor, said centre pin located radially by the vanes, said rotor mounted in the eccentric chamber of the stator, the outer pump chamber formed between said stator and outer periphcry of the rotor communicates with the peripheral inlet and discharge ports, the inner pump formed between the inner periphery of the rotor and centre pin communicates with the inlet and discharge ports in the face of the cylindrical chamber of said stator, fluid pressure from at least one of the discharge ports acting upon the end of the abutment and within the central bore of the rotor, and means interposed between the end of the ,centre pin and inner end of the central bore in the rotor for exerting a supplementary force in addition to the fluid pressure.

'3. A rotary pump comprising a stator having a cylindrical chamber, with an inlet and discharge port at diametrically opposite positions at the periphery of the chamber, and an inlet and discharge port situated at opposite positions in one face of the chamber, an eccentric liner fittedto the cylindrical chamber of the stator, a rotor provided at one end with a driving shaft and formed with a central bore which communicates with radial slots, a vane slidingly mounted in and a helical spring mounted in the recessed abutment and inner end of the centrol bore tending to supplement the fluid pressure.

ALAN WILLIAM SAY. 

